% This file is part of CWEB.% This program by Silvio Levy and Donald E. Knuth% is based on a program by Knuth.% It is distributed WITHOUT ANY WARRANTY, express or implied.% Version 3.0 --- June 1993 (works also with later versions)% Copyright (C) 1987,1990,1993 Silvio Levy and Donald E. Knuth% Permission is granted to make and distribute verbatim copies of this% document provided that the copyright notice and this permission notice% are preserved on all copies.% Permission is granted to copy and distribute modified versions of this% document under the conditions for verbatim copying, provided that the% entire resulting derived work is distributed under the terms of a% permission notice identical to this one.% Please send comments, suggestions, etc. to levy@@math.berkeley.edu.% The next few sections contain stuff from the file |"common.w"| that has% to be included in both |"ctangle.w"| and |"cweave.w"|. It appears in this% file |"common.h"|, which needs to be updated when |"common.w"| changes.First comes general stuff:@d ctangle 0@d cweave 1@<Common code for \.{CWEAVE} and \.{CTANGLE}@>=typedef short boolean;typedef char unsigned eight_bits;extern boolean program; /* \.{CWEAVE} or \.{CTANGLE}? */extern int phase; /* which phase are we in? */@ @<Include files@>=#include <stdio.h>@ Code related to the character set:@^ASCII code dependencies@>@d and_and 04 /* `\.{\&\&}'\,; corresponds to MIT's {\tentex\char'4} */@d lt_lt 020 /* `\.{<<}'\,;  corresponds to MIT's {\tentex\char'20} */@d gt_gt 021 /* `\.{>>}'\,;  corresponds to MIT's {\tentex\char'21} */@d plus_plus 013 /* `\.{++}'\,;  corresponds to MIT's {\tentex\char'13} */@d minus_minus 01 /* `\.{--}'\,;  corresponds to MIT's {\tentex\char'1} */@d minus_gt 031 /* `\.{->}'\,;  corresponds to MIT's {\tentex\char'31} */@d not_eq 032 /* `\.{!=}'\,;  corresponds to MIT's {\tentex\char'32} */@d lt_eq 034 /* `\.{<=}'\,;  corresponds to MIT's {\tentex\char'34} */@d gt_eq 035 /* `\.{>=}'\,;  corresponds to MIT's {\tentex\char'35} */@d eq_eq 036 /* `\.{==}'\,;  corresponds to MIT's {\tentex\char'36} */@d or_or 037 /* `\.{\v\v}'\,;  corresponds to MIT's {\tentex\char'37} */@d dot_dot_dot 016 /* `\.{...}'\,;  corresponds to MIT's {\tentex\char'16} */@d colon_colon 06 /* `\.{::}'\,;  corresponds to MIT's {\tentex\char'6} */@d period_ast 026 /* `\.{.*}'\,;  corresponds to MIT's {\tentex\char'26} */@d minus_gt_ast 027 /* `\.{->*}'\,;  corresponds to MIT's {\tentex\char'27} */@<Common code...@>=char section_text[longest_name+1]; /* name being sought for */char *section_text_end = section_text+longest_name; /* end of |section_text| */char *id_first; /* where the current identifier begins in the buffer */char *id_loc; /* just after the current identifier in the buffer */@ Code related to input routines:@d xisalpha(c) (isalpha(c)&&((eight_bits)c<0200))@d xisdigit(c) (isdigit(c)&&((eight_bits)c<0200))@d xisspace(c) (isspace(c)&&((eight_bits)c<0200))@d xislower(c) (islower(c)&&((eight_bits)c<0200))@d xisupper(c) (isupper(c)&&((eight_bits)c<0200))@d xisxdigit(c) (isxdigit(c)&&((eight_bits)c<0200))@<Common code...@>=extern char buffer[]; /* where each line of input goes */extern char *buffer_end; /* end of |buffer| */extern char *loc; /* points to the next character to be read from the buffer*/extern char *limit; /* points to the last character in the buffer */@ Code related to identifier and section name storage:@d length(c) (c+1)->byte_start-(c)->byte_start /* the length of a name */@d print_id(c) term_write((c)->byte_start,length((c))) /* print identifier */@d llink link /* left link in binary search tree for section names */@d rlink dummy.Rlink /* right link in binary search tree for section names */@d root name_dir->rlink /* the root of the binary search tree  for section names */@d chunk_marker 0@<Common code...@>=typedef struct name_info {  char *byte_start; /* beginning of the name in |byte_mem| */  struct name_info *link;  union {    struct name_info *Rlink; /* right link in binary search tree for section      names */    char Ilk; /* used by identifiers in \.{CWEAVE} only */  } dummy;  char *equiv_or_xref; /* info corresponding to names */} name_info; /* contains information about an identifier or section name */typedef name_info *name_pointer; /* pointer into array of \&{name\_info}s */typedef name_pointer *hash_pointer;extern char byte_mem[]; /* characters of names */extern char *byte_mem_end; /* end of |byte_mem| */extern name_info name_dir[]; /* information about names */extern name_pointer name_dir_end; /* end of |name_dir| */extern name_pointer name_ptr; /* first unused position in |byte_start| */extern char *byte_ptr; /* first unused position in |byte_mem| */extern name_pointer hash[]; /* heads of hash lists */extern hash_pointer hash_end; /* end of |hash| */extern hash_pointer h; /* index into hash-head array */extern name_pointer id_lookup(); /* looks up a string in the identifier table */extern name_pointer section_lookup(); /* finds section name */extern void print_section_name(), sprint_section_name();@ Code related to error handling:@d spotless 0 /* |history| value for normal jobs */@d harmless_message 1 /* |history| value when non-serious info was printed */@d error_message 2 /* |history| value when an error was noted */@d fatal_message 3 /* |history| value when we had to stop prematurely */@d mark_harmless {if (history==spotless) history=harmless_message;}@d mark_error history=error_message@d confusion(s) fatal("! This can't happen: ",s)@<Common...@>=extern history; /* indicates how bad this run was */extern err_print(); /* print error message and context */extern wrap_up(); /* indicate |history| and exit */extern void fatal(); /* issue error message and die */extern void overflow(); /* succumb because a table has overflowed */@ Code related to file handling:@f line x /* make |line| an unreserved word */@d max_file_name_length 60@d cur_file file[include_depth] /* current file */@d cur_file_name file_name[include_depth] /* current file name */@d web_file_name file_name[0] /* main source file name */@d cur_line line[include_depth] /* number of current line in current file */@<Common code...@>=extern include_depth; /* current level of nesting */extern FILE *file[]; /* stack of non-change files */extern FILE *change_file; /* change file */extern char C_file_name[]; /* name of |C_file| */extern char tex_file_name[]; /* name of |tex_file| */extern char idx_file_name[]; /* name of |idx_file| */extern char scn_file_name[]; /* name of |scn_file| */extern char file_name[][max_file_name_length];  /* stack of non-change file names */extern char change_file_name[]; /* name of change file */extern line[]; /* number of current line in the stacked files */extern change_line; /* number of current line in change file */extern boolean input_has_ended; /* if there is no more input */extern boolean changing; /* if the current line is from |change_file| */extern boolean web_file_open; /* if the web file is being read */extern reset_input(); /* initialize to read the web file and change file */extern get_line(); /* inputs the next line */extern check_complete(); /* checks that all changes were picked up */@ Code related to section numbers:@<Common code...@>=typedef unsigned short sixteen_bits;extern sixteen_bits section_count; /* the current section number */extern boolean changed_section[]; /* is the section changed? */extern boolean change_pending; /* is a decision about change still unclear? */extern boolean print_where; /* tells \.{CTANGLE} to print line and file info */@ Code related to command line arguments:@d show_banner flags['b'] /* should the banner line be printed? */@d show_progress flags['p'] /* should progress reports be printed? */@d show_happiness flags['h'] /* should lack of errors be announced? */@<Common code...@>=extern int argc; /* copy of |ac| parameter to |main| */extern char **argv; /* copy of |av| parameter to |main| */extern boolean flags[]; /* an option for each 7-bit code */@ Code relating to output:@d update_terminal fflush(stdout) /* empty the terminal output buffer */@d new_line putchar('\n') @d putxchar putchar@d term_write(a,b) fflush(stdout),fwrite(a,sizeof(char),b,stdout)@d C_printf(c,a) fprintf(C_file,c,a)@d C_putc(c) putc(c,C_file)@<Common code...@>=extern FILE *C_file; /* where output of \.{CTANGLE} goes */extern FILE *tex_file; /* where output of \.{CWEAVE} goes */extern FILE *idx_file; /* where index from \.{CWEAVE} goes */extern FILE *scn_file; /* where list of sections from \.{CWEAVE} goes */extern FILE *active_file; /* currently active file for \.{CWEAVE} output */@ The procedure that gets everything rolling:@<Common code...@>=extern void common_init();